This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Low temperature NADH/Fp (reduced nicotinamide adenine dinucleotide/oxidized flavoproteins) fluorescence imaging or "redox scanning" has been developed to image the in vivo mitochondrial redox states of tissues on the basis of the redox ratios (Fp/NADH or Fp/(NADH+Fp)) and may be useful for clinical diagnosis and treatment of cancer given the central role of mitochondria in cellular metabolism, apoptosis and signaling transductions. Previously we have applied this technique to a panel of human melanoma mouse xenografts with different metastatic potential and identify Fp redox ratio correlates highly significantly with the aggressiveness of these melanomas. Colon cancer is the third most common cancer in US men and the second most common cancer in US women of Hispanic, American Indian/Alaska Native, or Asian/Pacific Islander ancestry, and the third most common cancer in white and African American women. Its death rate ranked third for both men and women in US. In this subproject we aim to achieve 1) redox imaging of colon cancer mouse xenografts with different status of p53; 2) redox imaging of colon cancer mouse xenografts receiving a chemotherapy;3) study of the connection and interaction between p53 and mitochondrial redox state;4) comparison of redox images between colon cancer with different aggressiveness.